Inter-Master Node Handover with Split-to-MCG Bearer Switching

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

During Inter-Master Node handover in EN-DC, the source eNB is unsure whether the target eNB decides to keep all or part of the split radio bearers terminated in the en-gNB, leading to uncertainty in handling the SN Status Transfer message and potential loss of dual connectivity context.

Innovation Solution

The target eNB or en-gNB transmits an indication to the source eNB about the bearer type change from a split bearer to an MCG bearer, allowing the source eNB to wait for or obtain the transmission status of data from the en-gNB, ensuring a successful handover.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the target eNB decides to change bearer type from split bearer to MCG bearer during handover, then the handover flexibility is improved, but the uncertainty in handling SN Status Transfer message increases and dual connectivity context may be lost

Engineering Contradiction:

Improvehandover flexibilityVSAvoiddual connectivity context retention

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The source eNB performs preliminary actions by determining which radio bearers will be changed from split bearers to MCG bearers before the handover is completed. The source eNB waits for transmission status of data associated with these bearers from the en-gNB before finalizing the handover, ensuring that necessary data is forwarded and dual connectivity context is preserved.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The source eNB receives feedback from the en-gNB regarding the transmission status of data associated with radio bearers that are subject to bearer type change. This feedback mechanism allows the source eNB to make informed decisions about data forwarding and ensures that the handover process maintains reliability while enabling flexibility in bearer type changes.

Inventive Principle:

Principle #23Feedback

2Reliability

If the source eNB waits for transmission status of data from en-gNB, then data integrity is improved, but handover time increases

Engineering Contradiction:

Improvedata integrityVSAvoidhandover time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The source eNB identifies in advance which radio bearers are subject to bearer type change and proactively waits for their transmission status from the en-gNB. This preliminary identification allows the system to focus only on specific bearers rather than all bearers, reducing the overall time required while maintaining data integrity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The source eNB applies partial action by selectively waiting for transmission status only for radio bearers that are subject to bearer type change, rather than waiting for all radio bearers. This selective approach reduces the handover time while still ensuring data integrity for the critical bearers that require type changes.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP4035495B1Device, method, apparatus and computer readable medium for inter-master node handover

Publication Date: 2025.12.31 NOKIA TECHNOLOGIES OY

Figure 1
Figure 2
Figure 3

AI summary

Embodiments of the present disclosure relate to for handover. In response to reception of a request for handover of a second device from a third device to a first device, the first device transmit to the third device an indication that a radio bearer for the second device is to be changed from a split bearer terminated in a fourth device to a Master Cell Group bearer terminated in the first device, the second device being in dual connectivity with the third and fourth devices. The first device receives from the third device a transmission status of data associated with the radio bearer.